Coal cutting bit and holder therefor



Sept. 14, 1948. F. L. FULKE COAL CUTTING BIT AND HOLDER THEREFOR F'iled June 25, 1945 INVENTOR. femwrl. F511. mg,

Patented Sept. 14, 1948 COAL CUTTING BIT; AND HOLDER THEREFOR Frank L. Fulke, Terre Haute, Ind., assignor to Frank Prox Company, Inc., Terre Haute, Ind.,

a corporation of Indiana .Application June 25, 1945, Serial No. 601,501

The present application is a continuation in part of my copending application Serial Number 474,044, filed January 27, 1943, for Coal cutting bit. and holder therefor (now Patent N0.

2,396,945), which, in turn, is a continuation in part of my prior application Serial Number 385,972 filed March 31, 1941, for Coal cutting bit and holder therefor, now abandoned.

A primary object of the present invention is to provide for the optional use of a multi pointed factory hardened bit in a cutter chain adapted also for the use of conventional one-half inch by one inch shanked mine bits; so as to permit the user to employ either the conventional mine bit ormy factory bit at will. A further object is to provide a plural-use bit madeof a small piece of steel so formed as to carry out the intentions and attain the objectives ofthe present invention. A

further object is to provide a positive and inexpensive keeper through which to associate my bit with a chain block formed with a socket adapted also to hold ordinary mine bits. A further object of the invention is to provide an assembly in which a one-piece holder or keeper element is associated with a plural-pointed bit to support the latter upon a miningmachine chainlink with a portion of the bit and a portion of the holder received within a socket formed in the link, with the keeper positioned wholly laterally on one side of the bit relative to the cutting path of the bit, so

that the bit directly engages, and is laterallysupported in one direction by, one lateral wallof the link socket, while the bit directly engages, and is laterally supported in the opposite direction byf the holder which, in turn, directly engages, and is laterally supported'in said last-mentioned direction by, the opposite lateral wall of said link sock-- et. A further object of the invention is to pro-.

vide, in an organization of the character under consideration, alternatively usable bits and hold-. ers. of variably complementary thicknesses, so

that, for instance, the operator may at one time usebits /8 thick with holders having a complementary thickness of and may at another time use bits thick with holders having a complementary thickness of /8", the novel association of the bit and the holder disclosed herein being efiective to support even so thin a holder against breakage under lateral stresses encountered in machine coal cutting. A further object of the invention is to provide, for use in holding a plural-pointed bit in a socketed mining machine chain link, a holder or keeper formed to engage one lateral surface of such bit and to engage certaln of the edges of said bit at a plurality of points 3 Claims. (01. 262 33) and in such relative positions as to holdsaid bit against movement with respect to the holder in the plane of the bit and in the direction of the active point thereof, while leaving the opposite lateral surface of said bit open to engagement with a lateral wall of the link socket, said holder, together with said bit, being insertable .in said link socket, so that the bit is laterally supported between a lateral wall of the link socket and-a surface of the holder, while the bit directly engages said link socket wall and the holder, and the holder directly engages the bit and the opposite lateral wall of the link socket. Further ob'jects of the invention will appear as thedescription proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific constructions illustrated and described, so long as the scope of the appended claims is not violated,

In the drawings,

Fig. .1 is a side view of a bit and keeper con-- structed ln'acco-rdanee with my invention and assembled in the standard socket of a standard chain block, parts being shown in section for clarity of illustration;

Fig.2 is a transverse section through the construction of Fig. 1;

Fig. 3 is a horizontal sectional view taken substantially on the plane indicated by the line 3 3 ofFig. 1;

Fig. 4 is an end view ofthe keeper of Fig. 1; Fig. 5 is a view similar to Fig. 1, but showing a modified form of bit and keeper; and

Fig. 6 is a sectional view taken substantiallyon" the planeindicated by the line 66 of Fig, 5. The problem of so constructing a factory bit and holder as to be received in a conventional mine bit socket having rectangular dimensions slightly greater than one-half inch by one inch,

,so as to permit the optional alternative use of either the factory bit or a standard mine bit is very complicated, and numerous attempts to solve that problem have failed of success. A principal difliculty is that of providing s'ufiicient strength in the factory bit-and holder to avoid breakage f either, while holding the dimensions 3 beyond the link, and may even ruin the link itself. The active point of the bit must be a, considerable distance away from any part of the holder or link. I consider one and a half inches to be a minimum necessary spacing of a new active point from the link, and that the point should be disposed at least one inch from any part of the holder. Shocks, either lateral or in the plane of chain travel applied at the working ends of the bit, exert a strong tendency to break the bit or the holder right at the mouth of the bit block socket. The available cross section at the mouth of the socket is so small that any form of holder formed with a central socket orrecess in the holder will be robbed of strength at this vital point by whatever part of its cross sectional area is displaced by any part of the bit inside the socket at or even near to the socket mouth.

But it is not possible to enlarge this bit block of ,thedeit receiveddnfthetsocket l0 and at least one and a fhalf inch'es of its length projecting ther f om," T e at a1 a sid 8 of-my gages directly against the wall 90f thesocket-w. The oppositelateral flat side l2 of my bit bears against a wall 13; of an intermediate keeper-element '3. 'The opposite lateral 'wall 1'4 01? the keeper en a es the sidewall I5of the socket in. The end wall f 6 of thelkeeper engages the end wall I1 of he o ket; WhilescreW ll en ag s t eading n wan iB oft e eeper.

'A pair of spac'ed'indentations lil and 19' are formed in the leading edge [8 of the keeper-3 for thepurposeof securing the keeper in the socket l0 QDtionally at either-of twopositions, whereby thejgage of the bitZ may be optionally set, atone andJa halfinQhes or on andseven-eighths inch'es from the block.

The wall [3 of-my keeper ,3 ensasodby the side I 2 of my bit'is the bottom or fioor o'flan indentation outlined by substantially,perpendicu1ar outstanding projections or walls ,[3 and (3" conforming in shape to the edge contour of either endportion oimy bit .2. Thrust .upon my bit-in theplane. of. chain travel istaken upon these walls or "projections which cannot shear off because they are su ported directly against .the end walls ofthesocket'lii. 'lsidethrustupon my bit in the direction of the keeper is transmitted-by .compression'throug'h the keeper directlyagainst late eral'wall I 5 oflthesocket; andlsidethrusts from the opposite direction aretransmitted directlyby the en agement of thelateral surfaceB- Of mybit against the lateral lwall..9 of the .bIOCknSOCkBt. The block socketside .walls are, of course, amply strong'to resist breakingoutwardly.

"Thelateral thickness .of my bit is greatest at its midpoint, to. resist break-age tapering toward its cutting ends. of this taper lies in the fact that,.with thetwallfl ofimy bit flatly en a ed against the wall 9,,oflthe socket, the active cuttingspoint of my bitris. positioned out, ofline with the socket wall. 9,.-and.direotly inv the o ntralr ane f t so' et, Wh re it Another distinct function i 4 will cut in the track in which the socket was de signed to present the cutting point of an ordinary mine bit, it being obvious that my bit is far less in thickness than a standard mine bit shank.

My keeper extends slightly beyond the link socket at 29. so that keeper wall [3 provides an upwardly extended lateral support for my bi and in ender to ,provide 1% Similar extended sup port at the opposite side of my bit, I provide an extension of socket wall 9 beyond the link by welding alongside that wall a block 2!, whose face 22 "provides an extension of the wall 5 beyond the socket mouth alongside my bit 2.

The projections .13 :and 13" are shaped to correspond to the contour of the received bit porztionrinoluding the notches 4. It will be perceived, therefore, that ,the bit cannot be displaced from its position within the indentation. The keeper 3 cannot :be displaced from the bit block socket because of the engagement of the nose of screw I l in one or the other of theindentations 19 or I 9 on t e lead n ed e of t k ep r N ma ly, the indentation A 9 is used; hutif a squeeze con,- dition arises, 'thekerf maybe widened by shift, ing the 'bitaand keeper assembly and enga n the screw LI! in ndentation l9.

In further consideration of the limitations im posed, and the governin dimensionsht will readily be apparent that in devising .rny improved bit and keeper I have contrived to satisfy all the exacting requirements involved. My bit 2,15 of a length to project one and a half inches outwardly beyond the block socket, and to present azsuflicient depth of engagement ofltheside sur-' face ;8 within the socket flla ainst socket wall .9, the length o mybit'locinglmore'jthan twice its width at, its midpoint. In order ,to'present active cutting ;,point I properly for cutting, permitting the notch 4 ,toseryte asa rake. angle belowmy cut}- tinepoinh; must I-leanthe major axis of my bit backward, which also relieves the end surface 23; whereby each cornerof mybit may .be successivelypositionedfor cutting, and may-in each instance providfi a front rake and a rear relief. Obviously, with a substantial portion of my bit ecei ed i hin ith sooket, I must, n order to ean mybit oar-wardly, p ovide that th ibod width of my bitibesnbstantially less vthanthe Width of a Slide wall .of the socket ,Ill, which is lightly mo than one i h to a mod e tandard minebits. I

Obviouslyalsogin Qrderxtointerpose my bitbetwefinithewa lllfl ofthe socketandthe bottomof he, ndentation. in the wall 13,. m ,bit thickness must be very sub tantially less than approxi mately flnehalflinchiwhich is the width of .the sQkQt.

Those familiar with ,theart vWill recognize the rime desira il ty of m cmplo m nt of k epe 3 interposedibetween ,inylbit and-the socket wall f5, bit; is meshed with. the keeper, by which I mean'thatfitis,partiallyembedded in an indentation in',the lateral surface ofthe keeper, said indentation conforming in. contour to the outline of'th? 81 1b@dde'd,portionr .ofxthe bit, wherebythe bit is, held againstrmovement with respecttc the keeper, The 1 keeper, oof x course, j is held against movem nt in t e socket hy screw l l enga in in, one or theother. of, the indentations, l9 anal-9 n keeper, Yet ,.I 163i]- ver rapidly unlock the kfieper reverse oriroplacethe bit,.an-d positively, relockuthe assembly, only a partial turn of thessorewil I being required. lcould oteachieve bese'ladvaa agos. if i1; att mp d: to upport: my bit .withoutlthei keeper interposedsat the: Side. of

the bit, or,with0ut the screwengaging the keeper. If .I attempted to socket my keeper to placemy bit into a central opening therethrough, the satisfactoryfoiihation of such a socket would be extremely .zdifiicultifnot impossible, and such a socket would load up with coal dust which would seriously interfere with the setting of bits, or the socket Walls might mash in under abrasion to interferewith-changing thebit. i

; If, instead of, the single, simply formed, and rugged keeper I have devised, I should try to employ two metalclamps to associate my bit with the block socket, these clamps would necessarily be so thin and weak (in view of the space limitations imposed by the standard socket) as, to be unreliable. Furthermore, it is highly desirable to use as few loose parts as possible. i

Preferably, the keeper is formed with passages, as at 24, topermit thedischarge of coal dust from the-indentation therein, and also to allow for burrsforming at the cutting points during active wear thereof. i i

The block 2!, welded at the side of the bit socket in block I, obviously will not interfere with the use of ordinary one-half inch by one inch shanked standard mine bits, when desired. The block 2| and the outwardly extended portion of the keeper 3 have their extremitiesdisposed at least ,one inch from the active cutting point of my bit, so that there is little possibilityof injury to; these elements from coring, or in case a substantial portionof the extended end of the bit is abraded away rapidly against rock.

The walls of theindentation in my keeper are of substantially less dimension than the thickness. of my bit, as is clear from a consideration of Fig. 3. This arrangement is desirable in order to prevent dirt, accumulation, and a very slight projectionof these walls l3 and l3",is sufficient, in,coordination with the socket walls, to retain the bit in operative position.

It will also be apparent that I may, with the simple construction provided, accomplish the extremely desirable objective of permitting the user a choice of several sizes 'of factory bits to perform the operations desired and indicated by the user's particular cutting conditions. The bit illustrated, with itsrelatively thin body and slender piercing point isideal for easy cutting where minimum coal disintegration is desired.- If the user has hard impurities to cut, bits with heavier body sections and heavier duty cuttingpoints could be supplied, the use of such bits requiring merely an interchange of the keepers 3, thicker bits requiring thinner keepers.

Bits of the character herein disclosed must be as inexpensive as possible. The bit of'Figs. 1 to 4 may be readily sheared from thin, diamond bar stock, after which the four notches 4 may be easily out from it by four round punches operating at' a single stroke. Yet my bit, requiring only two or three ounces of steehprovides four successively usable ideal cutting points, the notches 4 properly meshing with the indentation in my keeper 3 regardless of which cutting point is placed in active position.

Under the trying limitation of space imposed, it will be seen that I do not rely, as often attempted heretofore, upon the strength of a bit holder, but rather upon the strength of my bit itself and the strength of the side walls of the bit block socket to which I directly transmit the stresses encountered in cutting, it being obviously impossible to break my simple keeper at any point by shocks from any direction, since the 6 forces acting upon it are almost entirely compressivey a a As has been said, a bit -ofirhomboidal face elevation, such as that illustrated in Figsw l to 4, produces the advantageous result of throwing the active cutting point-substantially into the median plane of the chain"; that is, into the position which would be occupiedby the point ofa standard, resharpenable shanked bit. But it isnot essential to the accomplishmentof some of -theuimportant. objects of my invention so tothrow: the active cutting point into that position; That is, the advantagesinherent in. the use of a small, plural-pointed, replaceable bit, together with .a one-piece shanked holder so constructed that the bit may be meshed with one lateral surface ofthe holderbefore introducing the assembled bit and holder into. the standard socket of a mining machine chain link in such a relation thatone lateral surface of the bit is pressed, by the holder, into engagement with acorrespondingly surfaced lateral wall of that socket, while the lateral surface of the holder opposite that surfacew ith which the bitismeshed, is pressedagainst the opposite lateral wall of the link socket, so that lateral stresses applied to the active point of the bit in one direction are directly resistedby the solid wall of the link, while such stresses impressed in the opposite direction are transmitted purely compressively -through the holder to the opposite side of the link, are so importanttlrat they quite overbalance any apparent disadvantage in the location of the cutting point in a position offset from the median plane of the link, It has for so long been considered necessary, in the mining machine chain art, to locate the cutting point midway between parallel planes containing respectively the lateral boundaries of the holder, that the thought of permitting the cutting point to lie outside that plane-is quite startling. But I have found that assemblies in which the active cutting point of the bit does lie outside that plane may be arranged to operate quite satisfactorily, land that the advantages inherent, in the concept above described completely outweigh anysdisadvantages arising from the unconventionalrelationship between the cutting point and thelink; One such assembly is illustrated in Figs. 5 and 6.

In this connection, it is to be noted that the late-rial dimension of the link' socket is standardly one half inch. Any bit in standard use has a cutting point which will produce a kerf at least one-eighth inch wide. Therefore, a bit of the character illustrated in Figs. 5 and 6 and having a thickness of $5" or more will cut at leastpartially lin the same path which would be cut by a bit standardly mounted. i i

Referring more particularly to Figs. '5 and 6, it will be seen that I have illustratedthereiri the same link block I with its socket l0 and set screw H. I have illustrated a bit 30 of rectangu lar cross section and 'triangularside elevation,

I formed to provide alternatively usable cutting angles. It may here be noted that in this assembly the elevational contour of the bit may be alternatively triangular, as illustrated, or trapezolidal, without affecting the other elements of the organization or the cooperation of the bit therewith.

A bit holder or keeper 36 of substantially rect tangular cross section is shaped to provide a fiat surface or floor 31 adapted to receive and support one lateral surface of the bit 3.0.; and thelatenal surfacebf said holdef'36 oppositethe surface 3Tfis adapted to engage and hesu'ppor ted by the latralwall i5 of thelink socket ll].v

With the surface ofthe .bit 3.0 in engagee ment with the surface 31 ofthe holder, theibitand-aholder assembly may be. inserted in the soeketfilll and, when so inserted, ,the' lateral sur iafie Al or th'ehit 30 is pressed against the lateral wall tor the socket 1.0; and is supported thereby. The surface of the keeper 36 constitutes the bottom or floor of ,an' indentation outlined by substantially perpendicular outstanding projections or walls 38, 39 and All, conforming in shape to theimidsection of the edge oontou'r of the hit 3D. It will-be readily apparent from an" examination Q-fE g. 5 that the bit 30 is meshed with the keeper @6111 the same sense in ,which thebit 2' is meshed with the keeperii, so that, neither bit canjbe' en"- gaged in the indentation of its keeper except by relative mo eme-nt in .a direction perpendicular Wthefloor of its indentation. Whenthe bit ,30 is villeshed with .itsikeeper .736, its leading'edg'e 3,3 lies in flush abutment with the indentation wall la, audits equiangularly' related edges 3'4" and 35 lie respectively in flush abutment with the indentationwalls 3,9 and A0. Thebit 30 is thus solidly supported, between the keeper surface 31 and soeketwall =9, uand between the indentation wall 38 and indentationwalls' 39 and 40, against any possihlemoyement with respect to the keeper 3,6. The keeper, in turn; is held against movementlwithin the socket I by Tthe engagement of thepnos'e of the set screw 1 I in .a socket 42 in the leading edge oi the shank of said keeper. The socket 42 may; if desired, be composite like the socketls, IQ of the keeper ,3.

Qbviously, the sbit 1.39 may be reversed to bring the point .32 into active position, ,in which'case, the bit edge 35 will engageithe indentation wall 39, while the bit edge 34'Will engage the inden'e tation wall 38. As is,clearly jtoibe seen in .Fig. 5, the indentation in the keeper ..fac'e includes aparallelwalled extensions in which is disposed theinactiveibit point, and which is equivalent in functionpto. the passages 24 ,of the embodiment of my invention illustrated in Figs. ,1 toll.

.frhe lateral. extent of the .walls issucnthat. hen he tweed-ke per as m y is inserted into the socket 10, said walls terminate short of th seeke w ll (Of course, the combined. ihi zie sp the k eper e bit is uehas tumor eli 'eaisnue fi n. h sqoket lfia I claim as. my invention:

lnIn combination with a cutter chain including a link having a socketfiadapted to receive and support ,a standard ,"rectangularly shanked mine hit, waikeeper having a side receivedlidsaid soeketand fitting OI-Ielateral wallof Said socket, the side of said keeper opposite v saidfiffirst-mentloned side ,being vtermed ;with .an indentation heY ne a wa n l n d o s idfirstm ntiened s de. and, a e mmin e b t r omb ie l ed e outline, one of said bit defining such outline fitting in said" indentation against said'iriclihd indentatidnwai'l; 'andaf angularly relatedwall "(it said ibis-fitting the opposite lateral'wall l e-said 5 socket; the maiinlumwhickriessof said 'bitjbe irig substantially lone-half "the Width" or said socket," wherebxr one" "sharp anglenf "th'rhdiii b'oi'dal o'utlin'e" iof' "said bit *is located within said socket and substanti'allyin 'contactwitli last-- hi'entioned'socket"'wall while "the otl1ersheirp angle 'thereef located outside" said socket and substantially in the" median'faiiial "plaiheof said soeket," the lateral "outline'of'the portion "of "said bitreceived" Withinsai'd indentation including at least" one reentrantsecti-on; "and the"outl"iife ot said indentation eonfomnng tosai'd laterareutline of said bit portion. ZfTh' combination with a cutter bit having four euttiiigfio'ints "defining the -co ners or "fa rectangle having maj0r' axis and amino; a es, or "a" holder for said ifbit removablfseciii'e d ta-e mining machine chain block and efielosi hg'fanfi seeming m placesiibst iitianythewnqreioi said bitl'yi'iig on "title side or said 'minor' aids" and holdiiig 'the" maitrsxis of said bit inclined outwardly and rearwardly with respect tdaplan'e 'pei p'ridiamante the iine'oi'ehain movement.

I n ecmtmenmr 'witl'i'arriiffihgn labhine cutter' el iain in'cluding a link navinga' siicket;""a pluralqbointed bi-t a keeper, said 'keepeihav irig a surface generally parallefwith "the plane 'of main movement", an'd said "surface *bdifig formed with arf'inden't'ationhquiidedby *wans eneral-1y jiiern'endieuiar'to such surr e "afnd eerres onqme n'rcontoar td'aportioii r the pantie ef sa'id 'bitj s'aid portion 'of' s'aid'bit' logifig enter: ahl'e' in said"indehtatienfonly by relative In ii -sa d bit "and keeper iri-"a d'irectio' sutstaiiti-ally' p l-aria to saidwalls, ails s'a'id anwkeeperessemtit saving" a portion slm' 'ilt ou sly enterable in'saidlirik soeket'w' itH Qn "s f aee bf"sai d"l$it substantl'allyparallelWithv s 7 1 planter-sai them fr'novejnienteng'elgifig" a seesteritialiy'tsrtilerwen "bfsaid sdeketff witKtfie otttsitt surfac er said hitlenga'gi'rig thehottdm; or is in entat on: andwith'thef' s'ifde ti sai keeper Topposite"theifir{s r'nen t'iqned slurfa'ee was of trig-aging stair ream-tenet eepp its and sii hstdfit'ially "parallel tds idfirs't-meh tiqfied 7 east 'threadedlyrhoiinte'dih A kand enga ing "said teeter, wheres-r sat;- tit and-keeper assernbly is 'lqekfdifisaidsoket.

REFERENCES .CITED J- lei. 3' a. --.r\ J: sw n ees ar s es ate twe we UNITED STATES PATENTS The foll '1; 265%? 1 71 2315 *zfset ais 

